I can fill in a couple of the blanks.. I used to own a
B7500. There are NO cables. the joystick connects directly to the valve. The machine will easily move the arms and bucket at idle, of course not at the same speed they would move at high RPM's, but they will move at a useful rate. You should easily raise the front end of your tractor off of the ground by placing the bucket vertical and then lower the main lift arms. If you cannot do all of the above, then you have an issue. Check hydraulic fluid level, and when was the last time the hydraulic filter was changed? Also a leak in the suction line going to the pump can allow air to ingress into the pump and would perhaps cause these issues.